1. Field of the Invention
The present invention relates to an optical diffuser, which has a transparent base body with a first surface, which is divided into facets and in which each facet has an elevation or a depression correlated or associated with a second curved surface.
2. Description of the Related Art
The optical diffuser can be used as a lens for a headlight. Also the optical diffuser can be used in an open-face spotlight for film, television, for stage or for architectural lighting and for photographic purposes.
EP 0 961 136 A2 discloses an optical diffuser with a diffusing body, whose surface is divided into facets. Each facet has an elevation with a spherical surface, which acts as a lens. The facets have a regular hexagonal edge contour, so that the arrangement of EP 0 961 136 A2 can be characterized as a honey-comb.
In practical applications this optical diffuser is characterized by its hexagonal light field, which is distinctly sharp-edged. The term “sharp-edged light field” means that there is a distinct gradient in the light intensities in the light field plane at the edges of the light field. The light intensities have a central region with a plateau-like behavior, which follows the strong drop or large gradient at the edge of the light field directed in an inward direction.
Also when a discharge lamp is used, coloration can occur at the edge regions of the light field, which can have different shades and tones according to the type of discharge lamp used.